Outdoor low power LED lamp

Abstract

An LED based lighting fixture for street lighting includes a lighting head unit including a heat sink structure for dissipating heat. Below the heat sink structure is one or more LED circuit boards each including a plurality of low power LEDs oriented in a plurality of different directions. Light emitted from the lighting head unit is cast in a desired pattern of disbursement. A lens unit is attached to the bottom side of the lighting head unit covering the LED circuit board. The lighting fixture includes a mounting unit for mounting the lighting head unit to a fixed structure such that an angle of the lighting head unit may be adjusted to direct the pattern of disbursement of light cast from the lighting head unit to a desired direction.

1. An LED based lighting fixture for street lighting, comprising:
 a lighting head unit including, on a top side thereof, a heat sink structure for dissipating heat and, below the heat sink structure, a flat LED circuit board comprising a plurality of low power LEDs oriented on the LED circuit board in a plurality of different angles with respect to the LED circuit board such that light emitted from the lighting head unit is cast in a desired pattern of disbursement; 
 a lens unit attached to the bottom side of the lighting head unit covering the LED circuit board; and 
 a mounting unit for mounting the lighting head unit to a fixed structure, the mounting unit being adjustably connected to the lighting head unit such that an angle of the lighting head unit, relative to the fixed structure, is adjustable to direct pattern of disbursement of light cast from the lighting head unit to a desired direction. 
 
     
     
       2. The lighting fixture of  claim 1 , wherein the heat sink structure comprises an aluminum ribbon with a series of projections extending tangentially therefrom, wherein the aluminum ribbon comprises aluminum or an alloy thereof. 
     
     
       3. The lighting fixture of  claim 2 , wherein the aluminum ribbon has head-and-shoulders shaped cross section or a plurality of petal extensions. 
     
     
       4. The lighting fixture of  claim 1 , wherein the LED circuit board is ceramic and conducts heat from the plurality of low power LEDs to the heat sink structure. 
     
     
       5. The lighting fixture of  claim 1 , wherein the plurality of low power LEDs are organized as a plurality of identical clusters wherein each cluster comprises LEDs oriented in a plurality of different directions relative to the orientation of the lighting head. 
     
     
       6. The lighting fixture of  claim 5 , wherein the identical clusters are arranged in rows and columns and are spaced equally from one another. 
     
     
       7. The lighting fixture of  claim 6 , wherein the identical clusters are arranged as seven columns and four rows, with the rows run along a longest axis of the lighting fixture, wherein each identical cluster comprises sixteen low power LEDs oriented in a plurality of different directions relative to the orientation of the lighting head unit. 
     
     
       8. The lighting fixture of  claim 1 , wherein the plurality of low power LEDs together draw from between 25 Watts and 60 Watts maximum power. 
     
     
       9. The lighting fixture of  claim 1 , wherein the lens unit comprises a single convex covering that covers the entire LED circuit board and attaches directly to the lighting head unit such that the LED circuit board is hermetically sealed and impervious to moisture. 
     
     
       10. The lighting fixture of  claim 1 , further comprising a module base that is attached at one end to the lighting head unit and at another end to the mounting unit, the module base unit housing a power supply unit for supplying power to the LED circuit board, the power supply unit being configured to accept a range of input voltages from 85 Volts to 267 Volts while providing a constant output voltage to the LED circuit board. 
     
     
       11. The lighting fixture of  claim 10 , wherein the heat sink structure and the lens unit together form an approximate cylinder with a fixed radius and a radius of the module base is less than the fixed radius of the heat sink structure together with the lens unit. 
     
     
       12. The lighting fixture of  claim 1 , further comprising a thermal conductive paste between the LED circuit board and the heat sink structure. 
     
     
       13. An LED based lighting fixture for street lighting, comprising:
 a lighting head unit including, on a top side, a heat sink structure for dissipating heat and, on a bottom side, a plurality of flat LED circuit boards, each board comprising a plurality of low power LEDs oriented on the LED circuit board in a plurality of different angles with respect to a respective LED circuit board of the plurality of LED circuit boards such that light emitted from the lighting head unit is cast in a desired pattern of disbursement; 
 a lens unit attached to the bottom side of the lighting head unit covering the plurality of LED circuit boards; and 
 a mounting unit for mounting the lighting head unit to a fixed structure, the mounting unit being adjustably connected to the lighting head unit such that an angle of the lighting head unit, relative to the fixed structure, is adjustable to direct pattern of disbursement of light cast from the lighting head unit to a desired direction. 
 
     
     
       14. The lighting fixture of  claim 13 , wherein the top side of the head unit and the heat sink structure attached thereto are contoured to prevent the collection of rain water. 
     
     
       15. The light fixture of  claim 14 , wherein the contour of the heat sink structure forms a wave shape with two peaks and a nadir therebetween, the nadir of the heat sink contour opening into a depression within the top side of the head unit for channeling water off of the light fixture. 
     
     
       16. The lighting fixture of  claim 13 , wherein the heat sink structure includes a plurality of fins for effectively dissipating heat. 
     
     
       17. The lighting fixture of  claim 13 , wherein the lighting head unit comprises aluminum for effectively conducting heat from the plurality of LED circuit boards to the heat sink structure. 
     
     
       18. The lighting fixture of  claim 13 , wherein a light sensing unit for sensing ambient light is attached to the top side of the lighting head unit for activating the LED circuit boards when the detected ambient light is below a predetermined threshold and deactivating the LED circuit boards when the detected ambient light is above a predetermined threshold. 
     
     
       19. The lighting fixture of  claim 13 , wherein the mounting unit includes a set of interlocking teeth for maintaining the desired angle of the lighting head unit relative to the fixed structure even when significant pressure is applied to the lighting head unit. 
     
     
       20. The lighting fixture of  claim 13 , wherein a power supply unit for supplying power to the plurality of LED circuit boards is contained within the lighting head unit. 
     
     
       21. The lighting fixture of  claim 13 , wherein the mounting unit includes a remote-controlled actuator for remotely adjusting the desired angle of the lighting head unit relative to the fixed structure. 
     
     
       22. The lighting fixture of  claim 13 , wherein the plurality of LED boards comprises two LED boards. 
     
     
       23. The lighting fixture of  claim 22 , wherein the plurality of LED boards comprises 4, 6 or 8 LED boards. 
     
     
       24. The lighting fixture of  claim 13 , wherein the desired pattern of disbursement of light of the lighting head unit is shaped to illuminate a particular area while minimizing light directed to surrounding areas. 
     
     
       25. The lighting fixture of  claim 24 , wherein the particular area includes one or more lanes of a roadway. 
     
     
       26. The lighting fixture of  claim 13 , wherein the lens unit is attached to the bottom side of the lighting head unit with a piano hinge on one side and one or more non -removable thumb screws on another side such that the lens unit is easily opened and closed without risking the loss of the screws.